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Report

Teaser, summary, work performed and final results

Periodic Reporting for period 1 - MARQUESS (Multiscale Analysis of AiRframe Structures and Quantification of UncErtaintieS System)

Teaser

Summary

MARQUESS will create a multi-scale modelling and simulation software platform for aircraft structural design and material selection to model and predict the behaviour of high performance polymeric composite and metallic materials. It will introduce a novel â€œbottom-up, top-downâ€ approach to the labour-efficient and computationally economic analysis of airframes. This integrated computational tool will enable the onset and progression of failure in airframe structures to be predicted, with quantification and management of the uncertainties at each modelling scale.
MARQUESS will empower European aircraft designers with a toolset that will enable them to make key design decisions regarding aircraft structural design and material choice with quantified data to enable right first time design and thereby reduce development time and cost and hence satisfying the demand for aircraft at a faster rate.

This overall aim will be satisfied through the following objectives, which will be achieved through execution of tasks in the relevant work packages.
To identify and establish the multi-scale modelling methods to be implemented within the project by undertaking a detailed survey of past work on multi-scale modelling of materials and structures
To select and define the Platform 2 demonstrators to be analysed, and hence to inform the final selection criteria by articulating the engineering data input and output parameters to be satisfied by the multi-scale modelling framework
To characterise the inaccuracies in results of numerical models arising from assumptions, approximations and discretisation, and select methods for incorporation into an error estimation tool for trial implementation and integration into the multi-scale modelling work
To finalise the criteria required for selecting the modelling strategies to satisfy the case studies decided and identify and fully specify three multi-scale modelling strategies for incorporation into the project software via the innovative top-down, bottom-up modelling strategy to provide trial implementations of the chosen methods for multi-scale modelling and the tool for uncertainty quantification
To produce an extendable, modular design for the multi-scale modelling system and to implement and validate the software which embodies the bottom-up, top-down multi-scale modelling, the graphical user interface and the modelling-related error estimation against a range of test cases
To employ the developed multiscale software system and assess and benchmark its accuracy and demonstrate the usefulness of the multiscale software system with modelling-related error estimation, and its user interface, on current problems and demonstrate the benefits in terms of shortened overall design process and potential to enable a simulation-based method of compliance

Work performed

WP1 The literature survey aspects of this task were taken to completion at project proposal stage. Additional material was added regarding adaptive mesh refinement, computational homogenisation, Generalised Method of Cells/ Transformation Field Analysis and cohesive modelling. A working case study was created by the Topic Manager to avoid conflicts with ABAQUS licence terms and to allow publishable results to be created. Furthermore, two simpler case studies were identified for testing of modelling strategies and of the workflow.
WP2 In the initial stages of the project the Topic Manager revised their interpretation of uncertainty quantification, with the focus being re-centred on the influence of modelling-related assumptions on the accuracy of the finite element predictions. A document focusing on sources of modelling uncertainties was therefore prepared. Appropriate interlaminar modelling practices were determined and uncertainties related to the use of â€œfeature modelsâ€ were estimated. A pragmatic approach to the evaluation of the effects of different modelling assumptions was developed, and detailed flowcharts drawn to document the proposed algorithms based on a simple form of interval analysis.
WP3 The selection criteria adopted were the ability to predict accurately and computationally efficiently the stresses in representative structures. Following discussions the topic manager on the exact requirements for the MARQUESS system, four modelling strategies were identified and assessed against the requirements for fidelity and efficiency. An approach was then selected. In practice, the implementation of the modelling strategies has taken place within the process of testing them, with the initial implementation being highly interventional data handling, moving towards scripting of the modelling processes using Python within the ABAQUS/CAE environment. Two test cases were identified to enable the shortlisted approaches to be trialled and evaluated.
WP4 The top-level architecture was chosen to be a Python plug-in for the ABAQUS/CAE workbench. A complete manual walkthrough of the multi-scale modelling process was undertaken, and the processes and data flows were documented and any ambiguities resolved. Data flow diagrams were drawn. A detailed list of queries, destinations and formats of data, was compiled and discussed with the Topic Manager. A detailed use case scenario was provided by the Topic Managers to inform the remainder of the design process.
WP6 Project, financial and risk management and administration activities are ongoing.

Final results

The key advances from the proposed software are articulated through the identified Key Innovations to create a flow of data between length scales.
K1 A unified framework for performing multi-scale simulation of aerospace structures made from metals and composites
K2 A hybrid top-down, bottom-up multi-scale methodology to combine the best aspects of sequential homogenisation and sub-modelling
K3 Automated generation of sub-models to facilitate highly refined modelling of large structures and improved exploitation of high performance
K4. Modelling-related error estimation integrated with the multi-scale analysis, enabling the effects of numerical approximations at all levels to be propagated through to structural predictions
K5 A novel holistic virtual prototyping strategy customised to suit aerospace applications
K6 An extendable software framework permitting further forms of sequential and concurrent multi-scale analysis
K7 Integrated graphical user interface for top-down and bottom-up multi-scale analysis and modelling-related error estimation

Results from MARQUESS will deliver outstanding benefits for Europe:
On the commercial level, aircraft designers will be able to use the methods and tools based on the holistic multi-scale modelling techniques being integrated and developed in the project to enhance their competitive offering
On the societal level, the modelling framework will provide quantitative justification that will enable the design of more environmentally friendly aircraft, which will bring benefits in terms of reduced pollution and even enhanced mobility as there will be better scheduling of aircraft maintenance resulting in more reliable operation
On the scientific and technical level, systematic integration of the length scales will open new avenues for research, e.g. better integration of models that demonstrate the results of nanomaterials in large structures